A light emitting element has a substrate of gallium oxides and a pn-junction
formed
on the substrate. The substrate is of gallium oxides represented by: (AlXInYGa(1-X-Y))2O3
where 0x1, 0y1 and 0x+y1. The pn-junction
has first conductivity type substrate, and GaN system compound semiconductor thin
film of second conductivity type opposite to the first conductivity type.
